Infrared foundations for quantum geometry II: Catalogue of all torsion-like theories including new ghost-tachyon-free cases

TL;DR

This paper systematically classifies all linear, parity-conserving models propagating a rank-three field relevant to torsion and high-energy physics, revealing that only vector torsion modes are propagated, contrary to previous literature.

Contribution

It provides an exhaustive, gauge-symmetry-based classification of torsion-like theories, including new ghost-tachyon-free models, with a focus on their physical propagation modes.

Findings

All models propagate vector torsion modes.

No scalar or pseudoscalar torsion modes are propagated.

Several unitary models are identified.

Abstract

The construction of consistent effective field theories in the infrared demands that models be defined by their underlying gauge symmetries, rather than by an arbitrary tuning of couplings or a cherry-picking of operators which may not be stable against radiative corrections. Adhering to this principle, we systematically derive all linear, parity-conserving models that propagate a pair-antisymmetric rank-three field on a Minkowski background. Such models are relevant not only to torsion, but to many areas in high-energy physics ranging from dual graviton formulations to string theory and higher-spin theories. Following this exhaustive classification, we extract several unitary models. In the context of torsion, the results are remarkable. None of the models we obtain propagate scalar or pseudoscalar torsion, in stark contrast to the literature focus. Instead, all models propagate one or more vector torsion modes.